The present invention relates to spherical fine particles of a colored resin which are used for colorants for coating, ink, plastic, fiber, rubber, etc., and for delusterants, fillers, toners and carriers for an electrostatic duplicating machine as well as cosmetics, etc. In more detail, the invention relates to spherical fine particles of a colored resin which are industrially useful and of a new type and made by incorporating an amino resin cured matter and an inorganic pigment into one body, and relates to a method for producing the particles.
Hitherto, various kinds of spherical fine particles of colored resin have been used for plastic, coating, ink, cosmetics, etc. and also, employed exhibiting a characteristic in the respective use. The spherical fine particles of colored resin are made by incorporating a dye or pigment with a resin into one body. Like this, the reason why the dye and pigment are used as one body being incorporated with the resin, but not used in their original form is due to elevation of an affinity to a polymer such as coating, ink, plastic, fiber, rubber, etc. Also, when the fine particles are spherical, compared with a case where the particles are not of such type, there is an advantage such as elevation of fluidity during a shaping process and also, in a case where the particles are used for coating, fiber, etc., an advantage so that a surface becomes smooth and that a filling amount can be increased.
Spherical fine particles of a colored resin obtained by combining a thermosetting resin such as a phenol resin, an epoxy resin, etc. or a thermoplastic resin such as an acrylic resin, a vinyl resin, etc. with an organic dye or an organic pigment are superior in clearness and coloring, while they have a tendency to be inferior in heat resistance, light resistance, solvent resistance, weathering resistance, bleeding resistance, etc. On the other hand, spherical fine particles of a colored resin, in which an inorganic pigment has been used for coloring, are superior to those, in which a dye has been used, in points of solvent resistance, light resistance, heat resistance, and bleeding resistance, and also, superior to those, in which an organic pigment has been used, in points of light resistance and heat resistance.
There have been known, as fine particles of a colored resin made by coloring a thermoplastic resin with a pigment, for example, fine particles of a colored resin obtained by blending and pulverizing a thermoplastic resin and a pigment (Japanese Official Patent Provisional Publication, showa 58-17169), spherical fine particles of a colored resin obtained by adding a pigment into a reaction mixture of a suspension polymerization etc. (Japanese Official Patent Gazette, showa 57-22324), and spherical fine particles of a colored resin obtained by coating a pigment after carrying out chemical or physical treatment on the surfaces of fine particles of a thermoplastic resin (Japanese Official Patent Provisional Publication, showa 63-10671).
Furthermore, as spherical fine particles of a colored resin made by coloring a thermosetting resin with a pigment, there have been known, for example, spherical fine particles of a colored thermosetting resin which is made by adding a pigment when synthesizing a thermosetting resin such as a phenol resin, an epoxy resin, etc. by a polyaddition and addition condensation reaction.
There is such a problem that the hitherto-known spherical fine particles of a colored resin, in which the forementioned thermoplastic resin is used, are inferior in heat resistance, solvent resistance, chemicals resistance, etc., bad in adhesion between the resin particles and pigment, and also, bad in smoothness on the surface of colored particles.
Besides, there is such a problem that the hitherto-known spherical fine particles of a colored resin, in which the forementioned thermosetting resin is used, are broad in particle distribution, are not fine particles of a real sphere type, have a defect that the particles are breakable, and become expensive by classification etc. being required in some of the use.